Impact of Structural Compliance of a Six Degree of Freedom Joint Simulator on Virtual Ligament Force Calculation in Total Knee Endoprosthesis Testing.

The AMTI VIVO™ six degree of freedom joint simulator allows reproducible preclinical testing of joint endoprostheses under specific kinematic and loading conditions. When testing total knee endoprosthesis, the articulating femoral and tibial components are each mounted on an actuator with two and four degrees of freedom, respectively. To approximate realistic physiological conditions with respect to soft tissues, the joint simulator features an integrated virtual ligament model that calculates the restoring forces of the ligament apparatus to be applied by the actuators.

Field phenotyping of ten wheat cultivars under elevated CO shows seasonal differences in chlorophyll fluorescence, plant height and vegetation indices.

In the context of climate change and global sustainable development goals, future wheat cultivation has to master various challenges at a time, including the rising atmospheric carbon dioxide concentration ([CO]). To investigate growth and photosynthesis dynamics under the effects of ambient (~434 ppm) and elevated [CO] (~622 ppm), a Free-Air CO Enrichment (FACE) facility was combined with an automated phenotyping platform and an array of sensors. Ten modern winter wheat cultivars ( L.

Investigating the function and design of molecular materials through terahertz vibrational spectroscopy.

Terahertz spectroscopy has proved to be an essential tool for the study of condensed phase materials. Terahertz spectroscopy probes the low-frequency vibrational dynamics of atoms and molecules, usually in the condensed phase. These nuclear dynamics, which typically involve displacements of entire molecules, have been linked to bulk phenomena ranging from phase transformations to semiconducting efficiency.

Combination of long-term CO labeling and isotopolog profiling allows turnover analysis of photosynthetic pigments in Arabidopsis leaves.

Background: Living cells maintain and adjust structural and functional integrity by continual synthesis and degradation of metabolites and macromolecules. The maintenance and adjustment of thylakoid membrane involve turnover of photosynthetic pigments along with subunits of protein complexes. Quantifying their turnover is essential to understand the mechanisms of homeostasis and long-term acclimation of photosynthetic apparatus.

Short hydrogen bonds enhance nonaromatic protein-related fluorescence.

Fluorescence in biological systems is usually associated with the presence of aromatic groups. Here, by employing a combined experimental and computational approach, we show that specific hydrogen bond networks can significantly affect fluorescence. In particular, we reveal that the single amino acid L-glutamine, by undergoing a chemical transformation leading to the formation of a short hydrogen bond, displays optical properties that are significantly enhanced compared with L-glutamine itself.

Quantitative Analysis of Minium and Vermilion Mixtures Using Low-Frequency Vibrational Spectroscopy.

Low-frequency vibrational spectroscopy offers a compelling solution for the nondestructive and noninvasive study of pigments in historical artifacts by revealing the characteristic sub-200 cm spectral features of component materials. The techniques of terahertz time-domain spectroscopy (THz-TDS) and low-frequency Raman spectroscopy (LFRS) are complementary approaches to accessing this spectral region and are valuable tools for artifact identification, conservation, and restoration. In this investigation of historical pigments, pure and mixed samples of minium (PbO) and vermilion (HgS) were studied using a combination of THz-TDS and LFRS experiments to determine the limits of detection (LOD) and quantitation (LOQ) for each compound with both methods.

Secondary organic aerosol reduced by mixture of atmospheric vapours.

Secondary organic aerosol contributes to the atmospheric particle burden with implications for air quality and climate. Biogenic volatile organic compounds such as terpenoids emitted from plants are important secondary organic aerosol precursors with isoprene dominating the emissions of biogenic volatile organic compounds globally. However, the particle mass from isoprene oxidation is generally modest compared to that of other terpenoids.

Terahertz Spectroscopy and Quantum Mechanical Simulations of Crystalline Copper-Containing Historical Pigments.

Terahertz spectroscopy, a noninvasive and nondestructive analytical technique used in art conservation and restoration, can provide compelling data concerning the composition and condition of culturally valuable and historical objects. Terahertz spectral databases of modern and ancient artists' pigments exist but lack explanations for the origins of the unique spectral features. Solid-state density functional theory simulations can provide insight into the molecular and intermolecular forces that dominate the observed absorption features as well as reveal deviations from simple harmonic vibrational behavior that can complicate these spectra.

Early biotic stress detection in tomato (Solanum lycopersicum) by BVOC emissions.

We investigated impacts of early and mild biotic stress on Biogenic Volatile Organic Compounds (BVOC) emissions from tomato in order to test their potential for early (biotic) stress detection. Tomato plants were exposed to two common fungal pathogens, Botrytis cinerea and Oidium neolycopesici and the sap-sucking aphid Myzus persicae. Furthermore, plants were exposed to methyl jasmonate (MeJA) in order to identify BVOC emissions related to activation of jasmonic acid (JA) signalling pathway.

Environmental conditions regulate the impact of plants on cloud formation.

The terrestrial vegetation emits large amounts of volatile organic compounds (VOC) into the atmosphere, which on oxidation produce secondary organic aerosol (SOA). By acting as cloud condensation nuclei (CCN), SOA influences cloud formation and climate. In a warming climate, changes in environmental factors can cause stresses to plants, inducing changes of the emitted VOC.

Atmospheric benzenoid emissions from plants rival those from fossil fuels.

Despite the known biochemical production of a range of aromatic compounds by plants and the presence of benzenoids in floral scents, the emissions of only a few benzenoid compounds have been reported from the biosphere to the atmosphere. Here, using evidence from measurements at aircraft, ecosystem, tree, branch and leaf scales, with complementary isotopic labeling experiments, we show that vegetation (leaves, flowers, and phytoplankton) emits a wide variety of benzenoid compounds to the atmosphere at substantial rates. Controlled environment experiments show that plants are able to alter their metabolism to produce and release many benzenoids under stress conditions.

A large source of low-volatility secondary organic aerosol.

Forests emit large quantities of volatile organic compounds (VOCs) to the atmosphere. Their condensable oxidation products can form secondary organic aerosol, a significant and ubiquitous component of atmospheric aerosol, which is known to affect the Earth's radiation balance by scattering solar radiation and by acting as cloud condensation nuclei. The quantitative assessment of such climate effects remains hampered by a number of factors, including an incomplete understanding of how biogenic VOCs contribute to the formation of atmospheric secondary organic aerosol.

Green leaf volatiles and oxygenated metabolite emission bursts from mesquite branches following light-dark transitions.

Green leaf volatiles (GLVs) are a diverse group of fatty acid-derived compounds emitted by all plants and are involved in a wide variety of developmental and stress-related biological functions. Recently, GLV emission bursts from leaves were reported following light-dark transitions and hypothesized to be related to the stress response while acetaldehyde bursts were hypothesized to be due to the 'pyruvate overflow' mechanism. In this study, branch emissions of GLVs and a group of oxygenated metabolites (acetaldehyde, ethanol, acetic acid, and acetone) derived from the pyruvate dehydrogenase (PDH) bypass pathway were quantified from mesquite plants following light-dark transitions using a coupled GC-MS, PTR-MS, and photosynthesis system.

Aerosol mass spectrometric features of biogenic SOA: observations from a plant chamber and in rural atmospheric environments.

Secondary organic aerosol (SOA) is known to form from a variety of anthropogenic and biogenic precursors. Current estimates of global SOA production vary over 2 orders of magnitude. Since no direct measurement technique for SOA exists, quantifying SOA remains a challenge for atmospheric studies.

Release of lipoxygenase products and monoterpenes by tomato plants as an indicator of Botrytis cinerea-induced stress.

Changes in emission of volatile organic compounds (VOCs) from tomato induced by the fungus Botrytis cinerea were studied in plants inoculated by spraying with suspensions containing B. cinerea spores. VOC emissions were analysed using on-line gas chromatography-mass spectrometry, with a time resolution of about 1 h, for up to 2 days after spraying.

RNAi-mediated suppression of isoprene biosynthesis in hybrid poplar impacts ozone tolerance.

Isoprene is the most abundant volatile compound emitted by vegetation. It influences air chemistry and is thought to take part in plant defense reactions against abiotic stress such as high temperature or ozone. However, whether or not isoprene emission impacts ozone tolerance of plants is still in discussion.

Methanol emissions from deciduous tree species: dependence on temperature and light intensity.

Methanol emissions from several deciduous tree species with predominantly mature leaves were measured under laboratory and field conditions. The emissions were modulated by temperature and light. Under constant light conditions in the laboratory, methanol emissions increased with leaf temperature, by up to 12% per degree.

Stomatal uptake and stomatal deposition of ozone in isoprene and monoterpene emitting plants.

Volatile isoprenoids were reported to protect plants against ozone. To understand whether this could be the result of a direct scavenging of ozone by these molecules, the stomatal and non-stomatal uptake of ozone was estimated in plants emitting isoprene or monoterpenes. Ozone uptake by holm oak (Quercus ilex, a monoterpene emitter) and black poplar (Populus nigra, an isoprene emitter) was studied in whole plant enclosures (continuously stirred tank reactors, CSTR).

Simultaneous growth and emission measurements demonstrate an interactive control of methanol release by leaf expansion and stomata.

Emission from plants is a major source of atmospheric methanol. Growing tissues contribute most to plant-generated methanol in the atmosphere, but there is still controversy over biological and physico-chemical controls of methanol emission. Methanol as a water-soluble compound is thought to be strongly controlled by gas-phase diffusion (stomatal conductance), but growth rate can follow a different diurnal rhythm from that of stomatal conductance, and the extent to which the emission control is shared between diffusion and growth is unclear.

Estrogen-active nonylphenols from an isomer-specific viewpoint: a systematic numbering system and future trends.

4-Nonylphenols (NPs) are very important environmentally relevant substances. They are persistent, toxic, endocrine-disrupting chemicals that are priority hazardous substances of the EU Water Framework Directive. NPs are degradation products of 4-nonylphenol ethoxylates (NPEs), a widely used group of nonionic surfactants.

Contribution to the structural elucidation of 10 isomers of technical p-nonylphenol.

Gas chromatography-mass spectrometry (GC-MS) with a 100 m capillary column at different oven temperatures is employed to separate isothermally p-nonylphenol into 21 isomers. Analysis of the resulting mass spectra of these isomers indicates that they could be classified into six groups with respect to different configurations of the alpha- and beta-C-atoms on the alkyl chains. Based on these basic structures nonylphenol isomers are synthesized and also characterized by GC-MS.

Description and evaluation of a sampling system for long-time monitoring of PAHs wet deposition.

In this paper a new electronically controlled year-round wet-only sampler for wet deposition of trace organic compounds (e.g. airborne PAHs) is described.

Endocrine disrupting nonylphenols are ubiquitous in food.

4-Nonylphenols (NPs) are common products of biodegradation of a widely used group of nonionic surfactants, the nonylphenol ethoxylates (NPEs). These compounds are known to be persistent, toxic, and estrogen active. There is a worldwide scientific and public discussion on the potential consequences of human long term dietary exposure to such endocrine disrupters.

Endocrine-disrupting nonylphenols--ultra-trace analysis and time-dependent trend in mussels from the German bight.

A very sensitive and efficient analytical procedure is presented for the determination of 4-nonylphenols (NP) in blue mussels by use of off-line coupling of high-performance liquid chromatography (HPLC) and gas chromatography with mass spectrometric detection (GC-MS). Combined steam distillation and solvent extraction were used to extract the analytes from the mussel samples. Before quantification by GC-MS the raw extracts were purified by normal-phase HPLC.